Identifying user by measuring pressure of button presses on user input device

ABSTRACT

In one embodiment, a method comprises receiving, by a user identifier circuit, a button pressure signature specifying a sequence of button pressure values sampled while a corresponding identified button of a user input device is pressed by a user; the user identifier circuit identifying the user of the user input device based on the button pressure signature; and the user identifier circuit outputting a message identifying the identified button and the identified user.

TECHNICAL FIELD

The present disclosure generally relates to identifying a user of a userinput device, the user input device implemented for example as a remotecontrol device of a television or set-top box, or a keyboard of a usercomputer, a cellphone, or a BlackBerry device.

BACKGROUND

User input devices utilize keyboard switches to detect a user pressing acorresponding key, where the keyboard switches are implemented accordingto a prescribed keyboard switch technology (e.g., mechanical switch,membrane switch, capacitive switch). Such keyboard switches have beenimplemented in user input devices such as remote control devices, orkeyboards of computers, cellphones, BlackBerry devices, etc. Variousbiometric and behaviometric techniques have been attempted to identifyusers of such user input devices employing keyboard switches, possiblyavoiding the necessity of a user performing a “logon” (e.g, useridentification and password) prior to a given user session. Biometricidentification techniques identify individuals based on unique physicalattributes, for example fingerprints, hand shape, face recognition, irisor retina pattern, voice pattern, etc., which can be extended to includepersonal tags such as active badges (e.g., RFID badges). Examplebehaviometric techniques that identify individuals based on theirbehavior include written signature analysis, computer mouse gestures,and keystroke behavior analysis. Keystroke behavior analysis is based ondetecting distinct typing patterns on a computer keyboard: typingpatterns are determined from assigning parameters to the typing acts,such as typing speed (e.g., keys pressed per a unit time interval),dwell time (i.e, how long a key is pressed), and flight time (timebetween one key press and the next key press).

Keystroke behavior analysis also can be applied to a remote controldevices for a television or set-top box, where user of the remotecontrol device at least can be classified into a certain user categorybased on viewer surfing (i.e., channel selection) patterns.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is made to the attached drawings, wherein elements having thesame reference numeral designations represent like elements throughoutand wherein:

FIG. 1 illustrates an example system having a user identifier circuitconfigured for identifying a user of a user input device, based on areceived button pressure signature specifying a sequence of buttonpressure values, according to an example embodiment.

FIG. 2 illustrates an example conversion of an analog pressure signal,generated by a pressure-sensitive buttonpad sensor circuit in responseto a user pressing an identified button, into a button pressuresignature specifying a sequence of button pressure values sampled whilethe user is pressing the identified button, according to an exampleembodiment.

FIG. 3 illustrates an example method by the system of FIG. 1 ofidentifying the user of the user input device of FIG. 1, according to anexample embodiment.

DESCRIPTION OF EXAMPLE EMBODIMENTS Overview

In one embodiment, a method comprises receiving, by a user identifiercircuit, a button pressure signature specifying a sequence of buttonpressure values sampled while a corresponding identified button of auser input device is pressed by a user; the user identifier circuitidentifying the user of the user input device based on the buttonpressure signature; and the user identifier circuit outputting a messageidentifying the identified button and the identified user.

In another embodiment, an apparatus comprises a user identifier circuitand an interface circuit. The user identifier circuit is configured forreceiving a button pressure signature specifying a sequence of buttonpressure values sampled while a corresponding identified button of auser input device is pressed by a user. The user identifier circuitfurther is configured for identifying the user of the user input devicebased on the button pressure signature. The interface circuit isconfigured for outputting, to a second device, a message identifying theidentified button and the identified user.

In yet another embodiment, logic is encoded in one or more tangiblemedia for execution and when executed operable to: receive a buttonpressure signature specifying a sequence of button pressure valuessampled while a corresponding identified button of a user input deviceis pressed by a user; identify the user of the user input device basedon the button pressure signature; and output a message identifying theidentified button and the identified user.

DETAILED DESCRIPTION

Particular embodiments enable identification of a user of a user inputdevice based on replacing existing keyboard switches that provide only adigital response to a user pressing the corresponding keyboard switch.The digital keyboard switches are replaced with pressure-sensitive(i.e., analog) buttons that can translate variable pressure applied by auser to at least one pressure-sensitive detector circuit. Thepressure-sensitive detector circuit can measure varying amounts ofpressure applied to a given input button by a user of the user input.The user of the device can be identified based on the detected pressureof the input buttons on the user input device. Hence, the use of apressure-sensitive detector circuit enables generation of a buttonpressure signature for a given input button of the user input device,enabling different users of the same user input device to bedistinguishable based on their respective behavior metrics with respectto pressing a given input button of the user input device.

Hence, the particular embodiments can distinguish between differentusers of the same user input device, based on comparing the buttonpressure signature (generated while a button is pressed) with knownattributes of the different users regarding their respective behaviormetrics in using the same user input device. If desired, the particularembodiments can identify the user of the input device using a prescribedalias (e.g., “user 1”, “user 2”, “user 3”), or by an actual useridentity based on the user having registered with the user input device.In addition, the particular embodiments also can identify the user froma single button press by the user, based on comparing the buttonpressure signature from the single button press with stored buttonpressure signatures in a user pattern database. Hence, a different usercan be identified each time the user input device is passed to adifferent user (e.g., multiple users contending for use of a TV remotecontrol).

Hence, the user inputs can be correlated to an identified user (with orwithout knowledge of the actual user identity), enabling automaticidentification of a user of the user device without the necessity ofmanual login by the user, and without the necessity of the user changinghis or her normal behavior in operating the user input device. Moreover,the user inputs correlated to an identified user can be supplied toexternal devices for more precise monitoring of user activities anddelivery of targeted content to the user.

FIG. 1 is a diagram illustrating an example system 10 for identifying auser of a user input device 12, according to an example embodiment. Theuser input device 12 can be implemented as a remote control device(e.g., a multifunction television remote) for use with a devicecontroller 14; the user input device also can be implemented as a gamecontroller such as the commerically-available Sony Playstation 2 DualShock Analog Controller (SCPH-10010), modified as described herein. Theuser remote 12 also can be implemented within a wireless telephone, acell phone, a computer keyboard, a personal digital assistant (e.g., aBlackBerry device), etc.

The example system 10 also can include a device controller 14 that cancommunicate with the user input device 12, and a prescribed server 16that is reachable by the user input device 12 or the device controller14 via a service provider network 18, for example a digital cablenetwork and/or a broadband Internet service provider network, etc.

The device controller 14 can be implemented as either a stand-alonecontroller, or as a controller within a consumer device controlled bythe user input device 12, for example a television set, a cable orsatellite set-top box, a game console (e.g., a Sony Playstation), orsome other consumer device such as a wireless telephony base station, acomputer appliance, a customer premises router, a Voice over IP gateway,etc.

The example user input device 12 can include a plurality ofpressure-sensitive buttons 20, implemented for example as plasticmembrane buttons. The user input device 12 also can include at least onepressure-sensitive buttonpad sensor circuit 22 configured for generatingan analog pressure signal in response to a user pressing thecorresponding button, enabling the user input device 12 to detect therelative pressure applied by a user to press any button 20 of the userinput device 12. The user input device 12 also can implement apressure-sensitive buttonpad sensor circuit 22 for each correspondingbutton 20 of the user input device. Conventional (i.e., digital)keyboard switches also may be added to the user input device 12, ifpreferred. The user input device 12 also includes a buttonpad controllercircuit 24, a memory circuit 28, and a wired or wireless interfacecircuit 26. The wired or wireless interface circuit 26 of the user inputdevice 12 can be configured with communication with a correspondingwired or wireless interface circuit 26 in the device controller 14 via awired or wireless (e.g., infrared or radio frequency (RF)) data link 33a; the interface circuit 26 also can be configured for establishing awired or wireless data link 33 b with a service provider network 18,bypassing the device controller 14.

FIG. 2 illustrates an example button input message 36 generated by thebuttonpad controller circuit 24, according to an example embodiment. Asdescribed below, the button input message 36 is sent to a useridentifier circuit for identification of the user that pressed thecorresponding button 20. Each pressure-sensitive buttonpad sensorcircuit 22 of FIG. 1 (e.g., 22 a) is configured for generating andoutputting to the buttonpad controller circuit 24 an analog pressuresignal 30 in response to detecting the corresponding button (e.g., “Ch+” for “Channel Up”, 20 a) being pressed by a user. If desired, any onebuttonpad sensor circuit 22 also can be configured to suppress theanalog pressure signal 30 until the user presses the correspondingbutton 20 with a sufficient pressure exceeding a prescribed minimumthreshold 31; hence, any one pressure-sensitive buttonpad sensor circuit22 can be configured to suppress the corresponding analog pressuresignal 30 if the corresponding detected button pressure is below theminimum threshold 31, illustrated by the dotted line.

The buttonpad controller circuit 24 can identify the analog pressuresignal 30 corresponding to the pressed button 20 a based on receiptthereof via a prescribed terminal input. The buttonpad controllercircuit 24 can digitize the analog pressure signal 30 for thecorresponding button (e.g., 20 a) based on sampling the analog pressuresignal 30 at prescribed time intervals (e.g., 50 milliseconds (ms))while the corresponding identified button 20 a is pressed by the user(e.g., above the minimum threshold 31), converting the samples 34 intodigital button pressure values across a prescribed dynamic range (e.g.,1 to 10), and storing the sequence 32 of button pressure values 34 in atangible memory circuit (e.g., within the buttonpad controller circuit24). Each of the button pressure values 34 that are sampled by thebuttonpad controller circuit 24 are illustrated in FIG. 2 as dots 34 onthe analog pressure signal 30. The buttonpad controller circuit 24 canthen generate the button input message 36, specifying a buttonidentifier 38 identifying the button (e.g., 20 a) pressed by a user, anda button pressure signature 40 that specifies the corresponding sequence32 of button pressure values 34 sampled by the buttonpad controllercircuit 24 while the user pressed the corresponding identified button20. The buttonpad controller circuit 24 also can output multipleconcurrent button input messages 36 in response to the usersimultaneously pressing multiple buttons (e.g., pressing “Shift” and“CH+” together), where the messages 36 can be output “concurrently”relative to the time that the respective buttons are pressed (e.g.,within 200 milliseconds); alternately, the button input messages 36 caninclude time stamp values, enabling the user identifier circuit 42 toidentify concurrent button presses based on similar time stamp indices(in milliseconds).

The buttonpad controller circuit 24 and/or the user identificationcircuit 42 also can implement thresholds in place of (or in addition to)implementing the threshold 31 in the buttonpad sensor circuits 2. Forexample, the buttonpad controller circuit 24 can implement a controllercircuit threshold to qualify a button press as a user input: if thepressure applied by the user does not exceed the controller circuitthreshold, the buttonpad controller circuit can output a “button pressedmessage” (as opposed to the button input message 36) that specifies thebutton pressed, but no signature 40, to indicate that insufficientpressure was applied by the user to constitute a user input.

Hence, the buttonpad controller circuit 24 can output multipleconcurrent messages in the event that multiple buttons 20 aresimultaneously pressed, where multiple concurrent button input messages36 can represent buttons pressed simultaneously by the user (e.g.,“Shift”-“CH+” for rapid channel changes), and a single input message 36generated concurrent with one or more button pressed messages ofadjacent buttons 20 can represent a case of “spill-over” (e.g., where auser applies a detected amount of pressure to a given button as a userinput, and the user also applies less pressure to adjacent buttons dueto finger or thumb size).

The button input message 36 (and/or any “button pressed message”)generated by the buttonpad controller circuit 24 can be supplied to thedevice controller 14 for identification of the user of the user inputdevice 12. Alternately, the button input message 36 can be supplied to auser identifier circuit 42 that can be implemented within the user inputdevice 12, described below.

The device controller 14 can include a wired or wireless interfacecircuit 26 for receiving the button input message 36 from the user inputdevice 12 (e.g., via an infrared or RF link). The device controller 14also can include a device controller circuit 44 for controlling deviceoperations (e.g., channel selection or navigation, volume control,etc.), a memory circuit 46, and a network interface circuit 48configured for establishing a data link 35 with a service providernetwork 18 for communications with a destination server 16.

The device controller 14 can include a user identifier circuit 42 and auser pattern database 50 stored within the memory circuit 46. Asillustrated in FIG. 1, the user identifier circuit 42 and the userpattern database 50 alternately can be implemented in the user inputdevice 12. Assuming the user input device 12 includes the useridentifier circuit 42 and the user pattern database 50 stored within thememory circuit 28, the user input device 12 can be configured forsending to the user gesture server 16 a user gesture message thatidentifies the user and the button pressed by the user, described infurther detail below with respect FIG. 3. Hence, the interface circuit26 of the user input device 12 can be configured for sending messagesdirectly to the user gesture server 16 via the service provider network18, eliminating the necessity of a device controller 14.

The user identifier circuit 42 is configured for identifying the user ofthe user input device 12 based on receipt of the button pressuresignature 40, and generating a message 52 containing the buttonidentifier 38 identifying the pressed button (e.g., 20 a) and a useridentifier 54 identifying the identified user of the user input device12. Hence, the user identifier circuit 42 (within the device controller14 or the user input device 12) can send the message 52 identifying theidentified button and the identified user to a prescribed destinationserver 16 in the service provider network 18. The message 52 can be usedby the server 16 in recording and tracking the user gestures (e.g.,socially relevant gestures by the user), enabling the user gestureserver 16 to provide content recommendations to the user of the userinput device 12 based on receipt of the message 52 identifying thebutton pressed by the identified user. Additional information regardingtracking socially relevant gestures based on recording inputs by anidentified user is described in commonly assigned, copending U.S. patentapplication Ser. No. 11/947,298, filed Nov. 29, 2007, entitled “SociallyCollaborative Filtering”.

As illustrated in FIG. 1, the user pattern database 50 can include, foreach stored user 62, a corresponding set 56 of stored button pressuresignatures 58 for respective pressed buttons 60 that have been pressedby the corresponding stored user 62. Although the stored button pressuresignatures 58 are illustrated as curves, each stored pressure signature58 preferably stored in the database 50 as a corresponding sequence 32of sampled button pressure values 34. As described below with respect toFIG. 3, the user identifier circuit 42 can apply prescribedinterpolation techniques, for example spline interpolation (e.g., aBezier curve), in order to determine whether a match exists between areceived button signature 40 from the buttonpad controller circuit 24and one of the stored button pressure signatures 58.

Any one stored button pressure signature 58 also can have acorresponding assigned context tag (for example, “C1” or “C2”) thatassociates the signature 58 with a corresponding “button input context”.In particular, a specific user may press a given button 20 usingdifferent pressure, depending on the context in which the button 20 waspressed. For example, if the user input device 12 is implemented as acomputer keyboard (e.g., a “QWERTY” type keyboard), a user may usedistinctly different pressures in pressing the “i” button depending onwhether the typed word was “I” (where the “i” button is the only typedbutton), “item” (where the “i” button is the first typed button in asequence), “tilt” (where the “i” button is the second typed button in asequence), etc. As illustrated in FIG. 1, the user pattern database 50can store a first set of the signatures 58 for a first context “C1”, asecond set of signatures 58 for a second context “C2”, etc. Hence, useof context tags enable multiple signatures 58 to be assigned to a singlepressed button 60 for a single user, where each context tag associatesthe corresponding signature 58 (for the specific button 60 pressed bythe specific user 62) to a corresponding stored button input contextwithin the database 50. Any one button input context for a signature 58can be stored in the database 50 as an identified sequence of pressedbuttons (e.g., “i-t-e-m” as context 1 for user “Jan”; “t-i-l-t” ascontext 2 for user “Jan”, etc.), or even a single button press (e.g.,“i” for user “Jan”). Hence, use of context-based signature matching(i.e., selecting a signature 58 for a specific button 60 based on amatching button input context identified by a detected sequence of oneor more pressed buttons) can provide even more precise matching ofsignatures by the user identifier circuit 42.

Any of the disclosed circuits of the user input device 12 and/or thedevice controller 14 can be implemented in multiple forms. Exampleimplementations of the disclosed circuits include hardware logic that isimplemented in a logic array such as a programmable logic array (PLA), afield programmable gate array (FPGA), or by mask programming ofintegrated circuits such as an application-specific integrated circuit(ASIC). Any of these circuits also can be implemented using asoftware-based executable resource that is executed by a correspondinginternal processor circuit such as a microprocessor circuit (not shown),where execution of executable code stored in an internal memory circuit(e.g., within the memory circuit 28 or 46) causes the processor circuitto store application state variables in processor memory, creating anexecutable application resource (e.g., an application instance) thatperforms the operations of the circuit as described herein. Hence, useof the term “circuit” in this specification refers to both ahardware-based circuit that includes logic encoded in one or moretangible media for performing the described operations, or asoftware-based circuit that includes a reserved portion of processormemory for storage of application state data and application variablesthat are modified by execution of the executable code by a processor.The memory circuit 28 and/or 46 can be implemented, for example, using anon-volatile memory such as a programmable read only memory (PROM) or anEPROM, and/or a volatile memory such as a DRAM, etc.

Further, any reference to “outputting a message” (or the like) can beimplemented based on creating the message in the form of a datastructure and storing that data structure in a tangible memory medium inthe disclosed apparatus (e.g., in a transmit buffer). Any reference to“outputting a message” (or the like) also can include electricallytransmitting (e.g., via wired electric current or wireless electricfield, as appropriate) the message stored in the tangible memory mediumto another network node via a communications medium (e.g., a wired orwireless link, as appropriate) (optical transmission also can be used,as appropriate). Similarly, any reference to “receiving a message” (orthe like) can be implemented based on the disclosed apparatus detectingthe electrical (or optical) transmission of the message/packet on thecommunications medium, and storing the detected transmission as a datastructure in a tangible memory medium in the disclosed apparatus (e.g.,in a receive buffer). Also note that the memory circuits 28 and/or 46can be implemented dynamically by the user identifier circuit 42, forexample based on memory address assignment and partitioning executed bythe user identifier circuit 42.

FIG. 3 illustrates an example method by the system of FIG. 1, accordingto an example embodiment. The steps described in FIG. 3 can beimplemented as executable code stored on a computer readable medium(e.g., floppy disk, hard disk, ROM, EEPROM, nonvolatile RAM, CD-ROM,etc.) that are completed based on execution of the code by a processor;the steps described herein also can be implemented as executable logicthat is encoded in one or more tangible media for execution (e.g.,programmable logic arrays or devices, field programmable gate arrays,programmable array logic, application specific integrated circuits,etc.).

As illustrated in FIG. 3, each pressure-sensitive buttonpad sensorcircuit 22 in the user input device 12 determines in step 70 whether thecorresponding detected button pressure (if any) exceeds the minimumthreshold 31. Assuming in step 70 that at least one button 20 (e.g., 20a) is pressed by a user applying at least the minimum pressure to exceedthe threshold 31, the corresponding buttonpad sensor circuit 22 (e.g.,22 a) generates the analog pressure signal 30 illustrated in FIG. 2.

The buttonpad controller circuit 24 samples in step 72 the detectedbutton pressure of the user input (as represented by the analog pressuresignal 30) every sampling interval (e.g., 50 ms), in order to compile instep 74 a sequence 32 of sampled button pressure values 34 over the timethat the analog pressure signal 30 is generated (e.g., while thedetected button pressure exceeds the minimum pressure threshold 31).Hence, the button signature 40 compiled in step 74 by the buttonpadcontroller circuit 24 specifies the sequence 32 of button pressurevalues 34 sampled while the corresponding identified button (e.g., 20 a)is pressed by the user.

The buttonpad controller circuit 24 outputs in step 76 at least onebutton input message 36 that contains the button identifier 38 for thepressed button (e.g., 20 a) and the corresponding button pressuresignature 40. Depending on implementation, the buttonpad controllercircuit 24 can forward the button input message 36 to a user identifiercircuit 42 within the user input device 12 (if available), or to theinterface circuit 26 for transfer to the user identifier circuit 42 ofthe device controller that is in communication with the user inputdevice 12. The buttonpad controller circuit also can output multiplebutton input messages 36 and/or button pressed messages for respectivebuttons that are pressed simultaneously by the user, including“spill-over” buttons (the messages are output “concurrently” relative tothe time that the respective buttons 20 are pressed).

The user identifier circuit 42 receives in step 78 at least one buttoninput message 36 (and also can receive button pressed messages), and inresponse attempts to identify the user of the user input device 12 usingprescribed pattern recognition techniques for recognizing the buttonpressure signature 40. For example, the user identifier circuit 42 candetermine in step 80 whether the user pattern database 50 includes anystored users 62. As used herein, the term “stored user” refers to a useridentifier 62 having at least one stored button pressure signature 58associated with the user identifier 62, regardless of whether the useridentifier 62 identifies an actual user identity, or whether the useridentifier 62 simply specifies an alias (e.g., “user1”, “user2”,“user3”) to distinguish from other users of the user input device 12. Ifthe user identifier circuit 42 determines in step 80 that the userpattern database 50 does not include any stored users 62, the useridentifier circuit 42 can generate in step 82 a prompt for display tothe user, offering the user an opportunity to perform a user login orregistration in order to provide an initial “training” of the useridentifier circuit 42 based on storing button signatures 58 forrespective pressed buttons 60 into the user pattern database 50. Notethat even if the user presses a key 20 to decline login, thecorresponding button signature of the pressed key can be stored in theuser pattern database 50 for subsequent recognition of the user. Asdescribed previously, actual registration of the user identity isoptional.

Assuming in step 80 that user identifier circuit 42 detects at least onestored user 62 within the user pattern database 50, the user identifiercircuit 42 can determine in step 84 whether the button pressuresignature 40 specified in the button input message 36 matches a storedbutton pressure signature 58 for the corresponding identified button 60,for example where the supplied button signature 40 for the correspondingidentified button “CH+” 38 matches the stored button pressure signature58 for the matching pressed button “CH+” 60. As described above, theuser identifier circuit 42 can apply known pattern matching techniques,for example spline interpolation, etc., in comparing the supplied buttonsignature 40 with the stored button signatures 58. Assuming a buttonsignature match in step 84, where the supplied button signature 40 forthe corresponding identified button 38 matches the stored buttonpressure signature 58 for the matching pressed button 60, the useridentifier circuit 42 can output in step 92 a user gesture message 52that specifies a user identifier 54 and the button identifier 38, fordelivery to the prescribed server 16 via the service provider network18.

Assuming in step 84 that the user identifier circuit 42 determines anabsence of any match between the supplied button pressure signature 40and the stored button pressure signature 58 for the matching pressedbutton 60, the user identifier circuit 42 can expand the search for amatching stored button pressure signature 58 throughout the user patterndatabase 50 in step 86, in order to determine whether any of the storedbutton pressure signatures 58 match the supplied button signature 40.The user identifier circuit 42 also can utilize patterns from multiplebuttons pressed simultaneously (e.g., “spill-over”). If in step 86 amatch is found between the supplied button signature 40 and any of thestored button pressure signatures 58 the user identifier circuit 42 canupdate in step 90 the user pattern database 50 for the matching user 62by recording the supplied button signature 40 into a correspondingpressed button entry 60 as identified by the button identifier 38. Themessage 52 specifying the user identifier 54 and the correspondingpressed button identifier 38 can then be output in step 92.

Hence, the user identifier circuit 42 in many instances can beconfigured for identifying the user after a single button press. If incertain instances additional button samplings are required in step 88before a user can be identified, the process can be repeated foradditional buttons collected within a prescribed sampling time interval,for example 15 seconds. As described previously, user identificationbased on matching button signatures 40 to stored signatures 58 also canbe implemented in step 84 based on the user identification circuit 42implementing context-based signature matching identifying a sequence ofone or more pressed buttons to an identifiable button input context.

If in step 88 a global signature match still cannot be obtained afterobtaining a maximum number of button samplings (e.g., sampling fivebutton presses), the user identifier circuit 42 can determine that a newuser is using the user input device 12, wherein the user identifiercircuit 42 can return to step 82 to offer a login or training procedurefor the new user.

According to the example embodiments, the user of a user input devicecan be identified based on the behavior metrics associated with theuser, namely the user-specific tendencies in pressing the buttons on theuser input device according to a distinguishable button pressuresignature. Since a given user may press different buttons according todifferent pressure characteristics (due to position of the correspondingbutton on the user input device), button pressure signatures can beaccumulated on a per-button basis, enabling identification of the user(relative to other available users of the user input device) from asingle button press. Hence, the user of the user input device can beidentified even in cases where the user input device is sharedconcurrently among different users contending for access to the userinput device.

While the example embodiments in the present disclosure have beendescribed in connection with what is presently considered to be the bestmode for carrying out the subject matter specified in the appendedclaims, it is to be understood that the example embodiments are onlyillustrative, and are not to restrict the subject matter specified inthe appended claims.

What is claimed is:
 1. A method comprising: receiving, by a useridentifier circuit, a button pressure signature specifying a sequence ofbutton pressure values sampled by a pressure-sensitive detector circuitat prescribed time intervals while a corresponding identified button ofa user input device is pressed by a user, the identified button beingone of a plurality of buttons on the user input device, thepressure-sensitive detector circuit configured for measuring, at theprescribed time intervals, variable pressure applied by the user duringa single user input via the corresponding identified button and inresponse generating the sequence of button pressure values as arepresentation of the variable pressure over time; the user identifiercircuit identifying the user of the user input device based on thebutton pressure signature, the plurality of said buttons arranged as adevice keyboard, enabling identification of the user based on thecorresponding button pressure signature from any one of the buttons; andthe user identifier circuit outputting a message identifying theidentified button and the identified user.
 2. The method of claim 1,wherein the identifying includes determining a match between the buttonpressure signature and at least one of stored button pressure signatureswithin a user pattern database, the user pattern database storing, forat least one stored user, a corresponding set of stored button pressuresignatures for a corresponding set of pressed buttons that have beenpressed by the one stored user.
 3. The method of claim 2, wherein thedetermining a match includes: determining whether the button pressuresignature matches a corresponding stored button pressure signature forthe corresponding identified button; and selectively determining whetherany of the stored button pressure signatures matches the button pressuresignature, based on a determined absence of a match between the buttonpressure signature and the stored button pressure signature for thecorresponding identified button.
 4. The method of claim 3, furthercomprising the user identifier circuit storing the button pressuresignature in the user pattern database for the corresponding identifiedbutton, based on a determined match between the button pressuresignature and at least one of the stored button pressure signatures. 5.The method of claim 2, further comprising generating the button pressuresignature by the pressure-sensitive detector circuit digitizing adetected analog pressure signal, the analog pressure signal generated bya pressure-sensitive buttonpad sensor circuit in response to the userpressing the identified button.
 6. The method of claim 5, wherein theuser input device comprises the user identifier circuit, thepressure-sensitive detector circuit, the identified button, thepressure-sensitive buttonpad sensor circuit, and the user patterndatabase.
 7. The method of claim 2, further comprising the useridentifier circuit storing the button pressure signature in the userpattern database for the corresponding identified button in thecorresponding set.
 8. The method of claim 7, wherein the storingincludes storing the button pressure signature during a userregistration operation.
 9. The method of claim 2, wherein theidentifying includes determining the match relative to an input contextof the identified button.
 10. The method of claim 1, wherein the messageis output to a prescribed destination server in a service providernetwork.
 11. An apparatus comprising: a user identifier circuitconfigured for receiving a button pressure signature specifying asequence of button pressure values sampled by a pressure-sensitivedetector circuit at prescribed time intervals while a correspondingidentified button of a user input device is pressed by a user, theidentified button being one of a plurality of buttons on the user inputdevice, the pressure-sensitive detector circuit configured formeasuring, at the prescribed time intervals, variable pressure appliedby the user during a single user input via the corresponding identifiedbutton and in response generating the sequence of button pressure valuesas a representation of the variable pressure over time, the useridentifier circuit further configured for identifying the user of theuser input device based on the button pressure signature, the pluralityof said buttons arranged as a device keyboard, enabling identificationof the user based on the corresponding button pressure signature fromany one of the buttons; and an interface circuit configured foroutputting, to a second device, a message identifying the identifiedbutton and the identified user.
 12. The apparatus of claim 11, furthercomprising a user pattern database configured for storing, for at leastone stored user, a corresponding set of stored button pressuresignatures for a corresponding set of pressed buttons that have beenpressed by the one stored user, the user identifier circuit configuredfor identifying the user based on determining a match between the buttonpressure signature and at least one of the stored button pressuresignatures.
 13. The apparatus of claim 12, wherein user identifiercircuit further is configured for determining the match based on:determining whether the button pressure signature matches acorresponding stored button pressure signature for the correspondingidentified button; and selectively determining whether any of the storedbutton pressure signatures of pressed buttons matches the buttonpressure signature, based on a determined absence of a match between thebutton pressure signature and the stored button pressure signature forthe corresponding identified button.
 14. The apparatus of claim 13,wherein the user identifier circuit is configured for storing the buttonpressure signature in the user pattern database for the correspondingidentified button, based on a determined match between the buttonpressure signature and at least one of the stored button pressuresignatures.
 15. The apparatus of claim 12, wherein the apparatusincludes the pressure-sensitive detector circuit, the pressure-sensitivedetector circuit comprising: a pressure-sensitive buttonpad sensorcircuit configured for generating an analog pressure signal in responseto the user pressing the identified button; the pressure-sensitivedetector circuit configured for generating the button pressure signatureby digitizing the analog pressure signal.
 16. The apparatus of claim 12,wherein the user identifier circuit is configured for storing the buttonpressure signature in the user pattern database for the correspondingidentified button.
 17. The apparatus of claim 16, wherein the useridentifier circuit is configured for storing the button pressuresignature during a user registration operation.
 18. The apparatus ofclaim 12, wherein the user pattern database is configured for storing aplurality of stored button pressure signatures for at least one pressedbutton relative to respective input contexts, the user identifiercircuit configured for determining the match relative to the inputcontext of the identified button.
 19. The apparatus of claim 11, whereinthe second device is a prescribed destination server in a serviceprovider network.
 20. An apparatus comprising: means for receiving abutton pressure signature specifying a sequence of button pressurevalues sampled by a pressure-sensitive detector circuit at prescribedtime intervals while a corresponding identified button of a user inputdevice is pressed by a user, the identified button being one of aplurality of buttons on the user input device, the pressure-sensitivedetector circuit configured for measuring, at the prescribed timeintervals, variable pressure applied by the user during a single userinput via the corresponding identified button and in response generatingthe sequence of button pressure values as a representation of thevariable pressure over time, the means for receiving further configuredfor identifying the user of the user input device based on the buttonpressure signature, the plurality of said buttons arranged as a devicekeyboard, enabling identification of the user based on the correspondingbutton pressure signature from any one of the buttons; and an interfacecircuit configured for outputting, to a second device, a messageidentifying the identified button and the identified user.
 21. Logicencoded in one or more non-transitory tangible media for execution andwhen executed operable to: receive a button pressure signaturespecifying a sequence of button pressure values sampled by apressure-sensitive detector circuit at prescribed time intervals while acorresponding identified button of a user input device is pressed by auser, the identified button being one of a plurality of buttons on theuser input device, the pressure-sensitive detector circuit configuredfor measuring, at the prescribed time intervals, variable pressureapplied by the user during a single user input via the correspondingidentified button and in response generating the sequence of buttonpressure values as a representation of the variable pressure over time;identify the user of the user input device based on the button pressuresignature, the plurality of said buttons arranged as a device keyboard,enabling identification of the user based on the corresponding buttonpressure signature from any one of the buttons; and output a messageidentifying the identified button and the identified user.